On Thursday, 1 September 2016 at 05:37:50 UTC, Manu wrote:
So, consider a set of overloads:
void f(T)(T t) if(isSomething!T) {}
void f(T)(T t) if(isSomethingElse!T) {}
void f(T)(T t) {}
I have a recurring problem where I need a fallback function
like the bottom one, which should be used in lieu of a more
precise match. This is obviously an ambiguous call, but this is
a pattern that comes up an awful lot. How to do it in D?
I've asked this before, and people say:
void f(T)(T t) if(!isSomething!T && !isSomethingElse!T) {}
Consider that more overloads are being introduced by users
spread out across many modules that define their own kind of T;
this solution is no good.
In the past, I have suggested using the "default" keyword to
specify a fallback function of this kind. I think it's a useful
pattern for generic algorithms that have optimized variants on
specific types for performance.
void f(T)(T t) if(isSomething!T) {}
void f(T)(T t) if(isSomethingElse!T) {}
void f(T)(T t) default {}
